Circuit breaker



FIG. 1 is a perspective view of an embodiment of a circuit breaker;

FIG. 2 is a front view of an embodiment of a circuit breaker;

FIG. 3 is a right view of an embodiment of a circuit breaker;

FIG. 4 is a left view of an embodiment of a circuit breaker;

FIG. 5 is a bottom view of an embodiment of a circuit breaker;

FIG. 6 is a top view of an embodiment of a circuit breaker; and,

FIG. 7 is a rear view of an embodiment of a circuit breaker.

The broken lines in FIGS. 1-7 form no part of the claimed design. 

The ornamental design for a “circuit breaker,” as shown and described. 